1. Field of the Invention
The present invention relates to a high frequency wave glass antenna for an automobile, which is appropriate to receive a digital terrestrial television broadcast in Japan (470 to 770 MHz), a UHF band analog television broadcast (473 to 767 MHz), a US digital television broadcast (698 to 806 MHz) or a UHF band (300 MHz to 3 GHz). The present invention also relates to a rear window glass sheet for an automobile, which includes the above-mentioned high frequency wave glass antenna for an automobile.
2. Discussion of Background
There has been known a high frequency wave glass antenna for an automobile as shown in FIG. 2, which is utilized for receiving a digital television broadcast (see, e.g., WO 2006/001486, page 1 and FIG. 1). In this prior art, a rear window glass sheet 14 includes a defogger, which comprises a plurality of heating wires 33 and bus bars 35, and the rear window also includes an antenna conductor 31 and a feeding point 32. The heating wire 34 at the highest position just under the antenna conductor 31 is formed in a meander shape. This arrangement reduces the adverse effect of the heating wires 33 and 34 on the antenna conductor 31 in a digital television broadcast band, improving the antenna gain in the digital television broadcast band.
However, this prior art has caused a problem in that the degree of reduction in the adverse effect of the heating wires 33 and 34 on the antenna conductor 31 is small in the digital television broadcast band, and that the improvement in the antenna gain in the digital television broadcast band is insufficient. This prior art has caused another problem in that the defogger is not compact in a vertical direction since the vertical width of the meander shape needs to be extended in order to improve the antenna gain.